#18940: Polynomials ignore the step argument in __getitem__
-------------------------------------+-------------------------------------
Reporter: pbruin | Owner:
Type: defect | Status: needs_info
Priority: major | Milestone: sage-6.10
Component: algebra | Resolution:
Keywords: | Merged in:
Authors: Peter Bruin | Reviewers:
Report Upstream: N/A | Work issues:
Branch: | Commit:
u/pbruin/18940-getitem_step | 1c56779b3140d12fbe5d0973cdcad0ac9dbb8054
Dependencies: #19409 | Stopgaps:
-------------------------------------+-------------------------------------
Changes (by jdemeyer):
* status: needs_review => needs_info
* milestone: sage-6.8 => sage-6.10
Comment:
Are you sure that the current behaviour is really what we want?
{{{
sage: pol = PolynomialRing(QQ, 'x')(range(10))
sage: pol
9*x^9 + 8*x^8 + 7*x^7 + 6*x^6 + 5*x^5 + 4*x^4 + 3*x^3 + 2*x^2 + x
sage: pol[2:]
9*x^9 + 8*x^8 + 7*x^7 + 6*x^6 + 5*x^5 + 4*x^4 + 3*x^3 + 2*x^2
}}}
I would have expected
{{{
sage: pol[2:]
9*x^7 + 8*x^6 + 7*x^5 + 6*x^4 + 5*x^3 + 4*x^2 + 3*x + 2
}}}
I know that this branch just extends the current behaviour. However, I
think we need to step back and define mathematically what should be
returned when asking for `pol[a:b:c]`. The current definition is not very
useful.
I think that `list(pol[a:b:c])` should be the same as `list(pol)[a:b:c]`,
except for different rules when the range is outside of `0 ...
pol.degree()`.
--
Ticket URL: <http://trac.sagemath.org/ticket/18940#comment:17>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
--
You received this message because you are subscribed to the Google Groups
"sage-trac" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To post to this group, send email to [email protected].
Visit this group at http://groups.google.com/group/sage-trac.
For more options, visit https://groups.google.com/d/optout.
